Systems for noncontact exchange of data are known in different designs and types. Inductively operating systems comprising radio frequency tags and reader/writer terminal and performing low frequency range that allows operating at relatively long distances, are well known in the art. Herein tags and cards employ using transmitting and receiving coils arranged in the terminal and in the card.
Several designs use electromagnetic coupling schemes including transmitting and receiving coils in the terminal and in the card. Other card designs utilize a capacitive interface between the card and terminal to transfer power. Capacitor plates are positioned on a surface of the card and corresponding plates are positioned in the terminal. When the card and terminal bring into contact, each pair of corresponding plates form a capacitor over which power may be transferred.
One example of the remotely operating cards, having electromagnetic coupling, is disclosed in U.S. Pat. No. 5,444,222 Inoue et.al., 1995 (Non-contact IC card, terminal for use with the non-contact IC card and non-contact IC card system having the non-contact IC card and the terminal, assignee Mitsubishi Denki Kabushiki Kaisha). Herein a non-contact IC card, a non-contact IC card terminal and a non-contact IC card system for performing data communication between the IC card and the terminal by using electromagnetic waves are arranged so that the IC card can reliably receive data transmitted from the terminal once the IC card is started up by a startup signal from the terminal. However the disclosed embodiment has an on-card battery to power microprocessor which controls data processing since the amount of a transferred electric power is not enough to energize on-card electronic circuit.
Next embodiment disclosed in U.S. Pat. No. 4,480,178 Miller, II et. al, 1984 describes a circuit for maximizing power transfer from a station to an interactive memory card via a capacitive interface. A reader system in the station generates an AC signal which provides operating power that is transferred to the card through the capacitive interface formed when the card is placed against a window on the station. The AC signal from the station is directed through a series resonant circuit to the card. The capacitive interface between the station and card make up the capacitive element of the resonance circuit while the series combination of the secondary of a transformer and an electrically variable inductor form the inductive element. Use of the variable inductor allows the station to tune the circuit to resonance and cancel the capacitive element, thereby maintaining maximum power transfer to the card.
An example of embodiment, utilizing a pure capacitive coupling to transfer power and data, is disclosed in U.S. patent application Ser. No. 08/677,412 Rozin et.al., Filed: Jul. 9, 1996, (the Israel patent application No.117,944 Filed on May 17, 1996) where the capacitive coupled bi-directional data and power transfer system is described, which includes a portable device with a first contact circuit formed from a pair of contact pads having an outer surface covered with a dielectric material. A processing unit is coupled to the first contact circuit. A host unit has a second contact circuit including a second pair of contact pads, which are also covered with a dielectric material. A host-processing unit is coupled to the second contact circuit. The first and second contact circuits are adapted to form a capacitive interface when the portable device is positioned proximate the host unit. The capacitive interface transmits both power and bidirectional data signals from the host unit to the portable device. And the same contacts are used to transmit bidirectional data signals between the portable device and the host unit.
However the disclosed designs can not operate at a distance more than few microns, i.e. in this system a card must be pressed by a receptacle part of terminal transducer when a card is inserted into slot of reader/writer. That guides to a huge restriction in a number of applications, for example in applications, which require the remote operation and short transaction time at once, such as mass transit and access systems, like underground, buses, railways and so on.
Embodiment disclosed in U.S. Pat. No. 5,594,233 Kenneth et.al., 1997 (Multiple standard smart card reader, assignee AT&T Global Information Solutions Company, Dayton, Ohio) comprising a card reader having a single entry slot for cards, and an electronic control means for controlling the operation of the reader. The reader further includes a smart card reading section incorporating a plurality of terminals respectively adapted to read contact smart cards, inductive contactless smart cards and capacitive contactless smart cards. A pair of endless belts is arranged to form a feed path there between. A card inserted through the entry slot is received between the endless belts and transported through the card reader and positioned in the smart card reading section so that smart card terminals on the card are located beneath corresponding smart card in the card reader. Data can then be read from the card if the card is a contact smart card, an inductive contactless smart card or a capacitive contactless smart card.
However, the disclosed embodiment is intended to operate in a mode where card is inserted into slot of reader/writer and do not permit operation at a distance between reader/writer device and a card.
The embodiment disclosed in U.S. Pat. No. 4,795,898, Bernstein et.al., 1989, (Personal memory card having a contactless interface using differential data transfer, Bernstein et.al., 1989, AT&T Bell Laboratories, AT&T Information Systems Inc.), describes a portable data card including memory means for storing data and processor means for processing data, energy coupling means for receiving magnetic energy transmitted from the reader/writer station and for converting the magnetic energy into electric energy for energizing the memory means and the processor means; and the capacitive coupling means and the energy coupling means providing in combination a complete communication interface between the data card and the reader/writer station.
However, the disclosed embodiment operates in a mode where card is inserted into slot of reader/writer and do not permit operation at a distance between reader/writer device and a card. In addition this embodiment requires a careful alignment of card and reader/writer receptacle transducer.
The purpose of the present invention is to provide a reliable method and device for reliable, stable and convenience operation of a smart card in contactless manner in inserted mode when significantly large electric energy may be transferred to power on-card smart electronics having a big mass storage, and in remote mode at a distance to provide a short time transactions when the same contactless card is used for access and mass transit applications.